JP2 DIGESTION
This eighth-grade science lesson is about the digestive system. Specifically, it focuses on saliva and the breakdown of starch into sugar. It is the 11th lesson in a sequence of 28 lessons on systems and the animal world. The lesson is 51 minutes in duration. There are 34 students in the class.
| Time | Caption |
|---|---|
| 00:00:14 | Uh, today let's summarize the results of the experiment we did yesterday, such as what happened to iodine and what happened to the Benedict's solution. |
| 00:00:26 | And then, things we understand from these results. On the right side of the report sheet there are two items writte, (1), (2) |
| 00:00:33 | (1) is what is learned from the iodine reaction. |
| 00:00:39 | (2) is what is learned from the Benedict's solution reaction. |
| 00:00:43 | I want you to summarize these two. I want you to discuss it in a group, but, don't form groups yet. |
| 00:00:54 | Uh, based on your results, we will eventually have a class summary. |
| 00:01:00 | Since it will be written down in your notebooks, please write the title of the experiment in your notebook. |
| 00:01:55 | Now you are going to form groups and discuss, but there is one thing I want to confirm before that. |
| 00:02:01 | That is Benedict's solution. Benedict's solution. |
| 00:02:06 | If we say Benedict's solution, I think you all have it written down in your notebook but, what is it? |
| 00:02:13 | Benedict's solution. Which one is it? |
| 00:02:17 | What is it used for? Makoto. How about you? |
| 00:02:21 | Benedict's solution. What do you think? |
| 00:02:23 | It's not written in my notebook. |
| 00:02:25 | It's not written in your notebook. I see. How about you, Tsuyoshi? |
| 00:02:29 | It is used to detect sugar. |
| 00:02:31 | Right. Yes. It is used to detect sugar. What do we do with it, Tsuyoshi? |
| 00:02:38 | Heat it. |
| 00:02:39 | Yes. Heat it. And then? What happens when we can tell that there is sugar? |
| 00:02:43 | It turns red. |
| 00:02:44 | It turns red. |
| 00:02:45 | [laughter]. |
| 00:02:46 | When it turns red. That's all right. It is red anyway. |
| 00:02:49 | The material we used this time was a substance called starch, and the other one which will be detected by the Benedict's solution is sugar, right? |
| 00:03:01 | I would like to touch on these two items just to explain something. |
| 00:03:07 | The substance called starch- in the second year, science division one, which we studied in the first semester. |
| 00:03:13 | All substances are made up of molecules. We talked about things like this, or like this, that are all made up of molecules. |
| 00:03:24 | But starch is- well, starch is also made up of molecules, but the molecules of starch are like this, long molecules, like this. Longer and longer. Long molecules. |
| 00:03:40 | At a glance, starch is a huge thing. The molecules are long. That's how it looks. |
| 00:03:47 | But on the other hand, sugar's molecule is short. Its molecule is short. At a glance, the molecule is small compared to starch. |
| 00:04:01 | When we include these issues in our consideration, the discussion will be easier. |
| 00:04:07 | So, today, you will form groups. |
| 00:04:11 | Uh, this... this needs to be focused... uh... yes. |
| 00:04:17 | This is same as your report sheet. |
| 00:04:19 | Summarize the result of your group, how the iodine reacted from A to D and how the Benedict's solution changed. |
| 00:04:31 | Four of you will summarize the results of groups one, two, three, four, etc. After that, summarize the results. |
| 00:04:39 | (1) What we can study from the iodine reaction; (2) what we can study from the Benedict's solution. |
| 00:04:44 | Four of you, or maybe if you have five people, the five of you think together and summarize it. I will let you present it later. |
| 00:04:50 | All right, I will let you form groups. Go ahead. |
| 00:05:04 | Unless you move it in this way... this one is... oh, like this. That's good. Very good. |
| 00:05:21 | What were the results in this group? |
| 00:05:24 | I have them written here. |
| 00:05:31 | I see. |
| 00:05:51 | That's good, right? This group is almost all at a good position. |
| 00:05:58 | What can we say from this? |
| 00:06:02 | A and C are... what is this? Black? Iodine does not become black in a reaction. |
| 00:06:09 | It was blackish, right? |
| 00:06:10 | //Yeah. |
| 00:06:11 | //Well, blackish- |
| 00:06:12 | Bluish purple. |
| 00:06:13 | Yes. This is a stage in which the bluish purple is very dark. |
| 00:06:15 | Dark purple. |
| 00:06:16 | Teacher. |
| 00:06:17 | Yes. |
| 00:06:18 | Do we write down the things to consider? |
| 00:06:19 | Yes. Think about the things to consider. Think about the things to consider. |
| 00:06:22 | And this part... these are supposed to have starch but... they are pale purple or white. Not white, rather transparent, I think. |
| 00:06:33 | Why did they become like that? |
| 00:06:37 | That's what you should consider. |
| 00:06:40 | Maybe because it cooled down. |
| 00:06:42 | Tsk. If iodine reaction- it reacts to iodine, does it mean it has starch or not? |
| 00:06:48 | It has. |
| 00:06:49 | It means it has starch, right? That means, in A and C, there is only starch to begin with, so it is natural that they are bluish purple. |
| 00:06:59 | It is B and D you have to think about. |
| 00:07:02 | In B and D, what else is in there besides starch? |
| 00:07:05 | Saliva. |
| 00:07:06 | Saliva is in there. Because saliva did something to the starch, they became like this, right? |
| 00:07:12 | Became like this, right? |
| 00:07:13 | That's what I want you to think about. |
| 00:07:14 | Yes. |
| 00:07:16 | And what are the conditional difference in the experiment between B and D? |
| 00:07:22 | What was the conditional difference between B and D? |
| 00:07:23 | Hot water and uh- |
| 00:07:24 | Ice //water. |
| 00:07:25 | //ice water. |
| 00:07:26 | //ice water. This one is warm. This one is cold. From these differences summarize your results. |
| 00:07:38 | The bluish purple is no longer bluish purple. That means the starch is? |
| 00:07:42 | Gone. |
| 00:07:43 | That means the starch is gone. How? |
| 00:07:48 | By hot water. |
| 00:07:49 | By hot water? |
| 00:07:51 | How about this group? |
| 00:07:55 | This group also had a good result. |
| 00:07:59 | But teacher, this one became pale reddish brown. |
| 00:08:05 | Well, pale reddish brown is sort of okay... they became a somewhat similar color, right? |
| 00:08:15 | But this one is orange. |
| 00:08:23 | Let me see... look, does the fact that they became bluish purple- they are bluish purple- mean they have starch or not? |
| 00:08:34 | They have. |
| 00:08:35 | They have, right? |
| 00:08:36 | A and C only have starch. Since they have nothing but starch, it is natural that they become bluish purple. |
| 00:08:45 | But in B and D, especially B, the bluish purple became pale. The fact that the bluish purple became pale means what happened to the starch? |
| 00:08:54 | It dissolved. |
| 00:08:55 | It dissolved or, in other words, the starch is disappearing, right? |
| 00:09:00 | In B and D, especially in B, what did we add? |
| 00:09:05 | What did we add? |
| 00:09:07 | What did we add to B? |
| 00:09:08 | Benedict's solution. |
| 00:09:09 | What? |
| 00:09:10 | Saliva. |
| 00:09:11 | We put spit in B. Spit, right? Slimy saliva. |
| 00:09:13 | Saliva. |
| 00:09:14 | That's what we added, right? |
| 00:09:16 | Then saliva is doing something to the starch. |
| 00:09:22 | It's all right to say dissolved or some kind of expression like that. From that, saliva (does what) to the starch? |
| 00:09:35 | Right? |
| 00:09:37 | Oh, one more thing. B and D are the same. They both contain saliva and starch. What is the conditional difference in the experiment? |
| 00:09:46 | Hot water and cold water. |
| 00:09:47 | That's right. Hot water and cold water. From that//- |
| 00:09:48 | //Teacher, that part is (inaudible). |
| 00:09:51 | Huh? Does this have a hole here? |
| 00:09:54 | Work hard. If you include that, I think you will have a good summary of the study. |
| 00:10:02 | Well, well. |
| 00:10:06 | What is it? |
| 00:10:09 | This group's results... This group's results are super. |
| 00:10:15 | If you cannot write a summary of the study from this good result, you are- |
| 00:10:20 | [mimetic expression] |
| 00:10:22 | You mean (inaudible)? |
| 00:10:24 | Did I say a thing like that? |
| 00:10:26 | No, no. |
| 00:10:27 | Well, so... should we look at it from here? |
| 00:10:31 | Well, A and C became all bluish purple, right? |
| 00:10:37 | Does that mean that there is starch or not? |
| 00:10:41 | There is. |
| 00:10:42 | There is, right? From the beginning to the end, there is always starch in these. |
| 00:10:45 | But in B and D, a difference appeared. In B and D, although both have starch, we added something special. What was that? |
| 00:10:54 | Saliva. |
| 00:10:55 | Saliva. Only those test tubes which have saliva have such a result.Especially B has a distinct change. It did not turn to bluish purple. That means what happened to the starch? |
| 00:11:05 | There is none. |
| 00:11:06 | Yes. The starch disappeared. The starch disappeared. |
| 00:11:09 | Saliva blah blah blah. |
| 00:11:15 | The one which we warmed up. |
| 00:11:16 | Yes, that's it. |
| 00:11:18 | A, B. |
| 00:11:19 | This is the one which we cooled down. |
| 00:11:20 | Well noticed. The conditional difference between B and D in this experiment is this one is warm, this one is cold. |
| 00:11:27 | If you compare the speed in which the starch disappears, which is faster, B or D? |
| 00:11:32 | B. |
| 00:11:33 | B is faster. That means... (inaudible). You must be able to figure it out. |
| 00:11:38 | Hm? |
| 00:11:39 | Almost. |
| 00:11:40 | One more push? |
| 00:11:42 | If you can summarize this result, you are in perfect shape. |
| 00:11:45 | Very good. Very good. |
| 00:11:48 | Okay, this group. |
| 00:11:55 | Looks good, looks good, looks good. Good. Good. |
| 00:12:13 | When we looked at it... everyone look, all right? |
| 00:12:17 | A and C got all bluish purple, right? Does that mean that there is starch or not? |
| 00:12:26 | There is. |
| 00:12:27 | There is, right? Because they turned to bluish purple. A and C have starch only, so it is natural to have an iodine reaction. |
| 00:12:34 | But B and D... especially in B, a change has occurred. |
| 00:12:40 | B has starch plus, like it is written here, saliva. |
| 00:12:45 | B's test tube which contains saliva changed from bluish purple to not changed to bluish purple... that's an odd way to say |
| 00:12:53 | It no longer turned to bluish purple, that means starch disappeared due to the saliva, right? |
| 00:13:06 | It will be good if you can write things like that in the summary of the study. |
| 00:13:09 | In addition to that, this group noticed that in comparing B and D, D did not turn pale around here, did it? |
| 00:13:19 | It may have. |
| 00:13:20 | It may have? |
| 00:13:22 | Around here, only here became pale. |
| 00:13:24 | It became pale? The conditional difference between B and D is the temperature, right? You noticed the difference in the temperature, right? |
| 00:13:34 | That's a good point. That's good. In addition to that... which one had Benedict's solution... Oh, they became the same color? |
| 00:13:44 | In that case, it will be difficult to write the summary of the study, huh? |
| 00:13:48 | Well, well, well, well, well. |
| 00:13:52 | Look. Look. |
| 00:14:05 | These are (the results of) one group. |
| 00:14:14 | Both of yours got this color? |
| 00:14:20 | Well, if (your results) are like that, you cannot write the summary of the study. Since they turned to the same color, you cannot compare. |
| 00:14:27 | This other group got these results. Why don't you think about it from these? |
| 00:14:30 | Only B is reacting. We cannot say from this that A has reacted. From these (results), think about parenthesis two of the study. Only B has reacted. |
| 00:14:52 | How about this group? Oh, nothing. What happened? |
| 00:14:56 | We don't understand. We don't understand. |
| 00:14:59 | You don't understand. Well then should we do it together? |
| 00:15:02 | You have nice results, you know? Here we go. |
| 00:15:06 | A and C all turned to bluish purple, right? |
| 00:15:10 | Yes. |
| 00:15:11 | Does that mean they have starch or not? |
| 00:15:15 | They have. |
| 00:15:16 | They have, right? From the beginning to the end, they all have starch. |
| 00:15:18 | However, B and D, especially B here, lost its bluish purple color. |
| 00:15:26 | B has starch in it just as A and C, but it has something plus starch. What does it have? |
| 00:15:31 | Saliva. |
| 00:15:32 | Yes, saliva. In the one which contains saliva, the bluish purple is no longer bluish purple. That means, the starch... due to the saliva- |
| 00:15:46 | Got eliminated. |
| 00:15:47 | Yes, yes. Something like that. |
| 00:15:48 | It got eliminated. Starch has disappeared. You can conclude like that. |
| 00:15:57 | Can we write the starch is gone? |
| 00:15:58 | Right, right. Expressing it like that is fine. |
| 00:16:00 | Hm, that's fine. |
| 00:16:06 | That's fine. |
| 00:16:07 | That's fine. |
| 00:16:09 | The guys have written nothing. |
| 00:16:12 | I'm not a man! |
| 00:16:14 | Oh, I'm sorry. |
| 00:16:15 | Next, how about the Benedict's solution? It didn't turn reddish brown... Oh, I see. |
| 00:16:21 | You put Benedict's solution in A and B, you put Benedict's solution in A and B, and when you heat it, only B has reacted. |
| 00:16:28 | That means, what's in B? |
| 00:16:29 | Sugar. |
| 00:16:30 | Sugar is in it. That means... as I said before... the starch in B has disappeared because of the saliva, and what is made? |
| 00:16:37 | Sugar. |
| 00:16:39 | Ohh. |
| 00:16:40 | Wonderful. |
| 00:16:41 | //Starch has disappeared. |
| 00:16:41 | //Thank you. [play on words] |
| 00:16:42 | [laughter] |
| 00:16:45 | You are welcome. |
| 00:16:48 | How about this group? |
| 00:16:50 | We have summarized most of it, even though we have not written yet. |
| 00:16:55 | This sentence is wrong though. |
| 00:16:57 | Whose answer is right? |
| 00:16:58 | I don't know whether this is right or not, but we are summarizing by talking, and I did most of the summarizing. |
| 00:17:04 | We were summarizing by talking. |
| 00:17:06 | So, shall we check? |
| 00:17:07 | Yes. |
| 00:17:08 | Ah! These are wonderful results as well. If you cannot summarize these results, you are... Kenji- |
| 00:17:14 | Yes. |
| 00:17:15 | Nothing. |
| 00:17:17 | Well, when we look at this, A and C are all purple, that means that the starch has reacted. That means that there is starch in A and C till the end, right? |
| 00:17:27 | But in B and D, (the circles) are colored red, which means that the starch has not reacted, iodine has not reacted, right? |
| 00:17:33 | This means that in B and D, we put starch and saliva, but due to the function of saliva, starch has blah blah blahed, has blah blah blahed. What is it? |
| 00:17:46 | Dissolved. |
| 00:17:47 | Yeah, dissolved. In normal language, it has disappeared. We can understand that starch has disappeared due to the function of saliva. |
| 00:17:57 | Then, what is the difference in the experimental conditions of B and D? |
| 00:18:00 | Temperature. |
| 00:18:01 | Temperature. B is? |
| 00:18:02 | Uh, 40 degrees. |
| 00:18:03 | Body temperature. |
| 00:18:04 | //Close to the body temperature. |
| 00:18:04 | //Yes body temperature, and D is? |
| 00:18:05 | Ice water. |
| 00:18:05 | It's cold. |
| 00:18:06 | Which has a faster rate of change in which starch becomes no longer starch, B or D? |
| 00:18:12 | B. |
| 00:18:13 | B is faster. That means that saliva's rate of effect on starch is... the temperature? |
| 00:18:19 | Faster when it is closer to the body temperature. |
| 00:18:20 | Ahh, wonderful. That's perfect. |
| 00:18:24 | We said that before. |
| 00:18:25 | In addition to that, which one becomes red brown? |
| 00:18:30 | B. |
| 00:18:31 | B. That means that while saliva changed the starch, what other than starch was made? |
| 00:18:37 | Sugar. |
| 00:18:38 | Ah. Kenji. |
| 00:18:39 | Yes. |
| 00:18:40 | You have good friends. |
| 00:18:41 | Yes. |
| 00:18:42 | //Are we friends? |
| 00:18:43 | //How about this group? |
| 00:18:44 | I didn't know that we were friends. |
| 00:18:50 | Are you writing now? |
| 00:18:56 | Let me check it. Let me see. Let me take a look at Takashi's. |
| 00:19:03 | This one, too. |
| 00:19:04 | We did not do the first one. |
| 00:19:05 | Oh, you didn't do the first one. |
| 00:19:06 | This one, too. |
| 00:19:10 | Ohh, it became reverse... Umm, what I want to check with you is that when they are bluish purple, when they are bluish purple. Does this mean they have starch or not? |
| 00:19:25 | They have. |
| 00:19:26 | They have, right? When they are not bluish purple, the starch is? |
| 00:19:30 | Not there. |
| 00:19:31 | Not there. Consider that. In the case of B, eventually, and in the case of D, from the beginning |
| 00:19:38 | When we compare B and D, in both cases the starch disappears. |
| 00:19:41 | Because of what? In B and D, there is starch plus what? |
| 00:19:45 | Saliva. |
| 00:19:46 | There is saliva. You have to figure out what the saliva did. In addition to that, what was the conditional difference between B and D? |
| 00:19:55 | Temperature. |
| 00:19:56 | Temperature. B is? |
| 00:19:57 | Forty degrees. |
| 00:19:58 | Forty degrees. D? |
| 00:20:02 | Cold. |
| 00:20:03 | Cold. |
| 00:20:04 | That means that... saliva works differently depending on the temperature. What was that? |
| 00:20:13 | You see that saliva works differently, right, depending on the temperature. |
| 00:20:16 | And then, reddish brown... orange... oh, both changed...then it is hard to write the summary. |
| 00:20:25 | So- |
| 00:20:37 | Because you cannot proceed to the conclusion when you have the same reaction- this is from a different group by the way- only B has reacted. Only B became reddish brown. |
| 00:20:48 | A did not react. I hope that you can come to a conclusion from this result. Right? |
| 00:20:59 | What is it, Nishi-kun? |
| 00:21:00 | I don't understand it. |
| 00:21:02 | Okay. |
| 00:21:03 | This group is left. |
| 00:21:05 | Yes. |
| 00:21:08 | What should we write in number two? |
| 00:21:10 | Is it because starch is made, that sugar is made? No, is it because the starch has disappeared, that sugar is made? |
| 00:21:16 | In the beginning of the class- look at that- the result of breaking up the long chain of starch is sugar. |
| 00:21:28 | Is it sugar because the long chain has been broken up? |
| 00:21:31 | Sugar is the result of what was originally big becoming small. Sugar. It is part of starch.// |
| 00:21:35 | //Part of starch is sugar? Because starch disappeared, sugar is made? |
| 00:21:40 | Well, you may say it in that way. |
| 00:21:42 | What is the best way to say it? |
| 00:21:45 | Well, we will summarize that at the end. |
| 00:21:50 | Then, this group last. How is it? |
| 00:21:52 | (inaudible) |
| 00:21:53 | Sorry, sorry. Which one? |
| 00:22:02 | Okay, Okay, you got the results. In this group, A and C are all bluish purple. That means, do these have starch or not? |
| 00:22:10 | They do. |
| 00:22:11 | They all have starch, right? Because they have only starch in them. |
| 00:22:15 | But B and D are no longer just bluish purple. So when we look at it, as time passes, does the bluish purple get lighter or darker? |
| 00:22:26 | Lighter. |
| 00:22:27 | It gets lighter, right? What's in B and D besides the starch? What is it? |
| 00:22:31 | Sugar. |
| 00:22:32 | Right. What? Sugar? |
| 00:22:33 | Not sugar. |
| 00:22:34 | Saliva. |
| 00:22:35 | Saliva. Hideki's saliva was real gooey. |
| 00:22:38 | Gooey? |
| 00:22:40 | That means, do B and D have or not have starch at one point? |
| 00:22:45 | They do not. |
| 00:22:46 | They do not. Starch is... because of what effect? |
| 00:22:51 | Saliva's effect. |
| 00:22:52 | That's right. Due to Hideki's saliva, starch has... disappeared. That's what you should write. Let me see. |
| 00:23:08 | In addition to that, what is the conditional difference between B and D? |
| 00:23:11 | Ice. |
| 00:23:12 | Right. //Ice and |
| 00:23:13 | //Ice and hot water. |
| 00:23:14 | Yes, hot water. Which one is hot water? |
| 00:23:15 | B. |
| 00:23:16 | B. What about D? |
| 00:23:18 | Ice. |
| 00:23:19 | Yes. Are these the same? Oh, these are exactly the same.... I see.... |
| 00:23:25 | Then it is hard to write about the different temperature. Okay, then you can write only this part. |
| 00:23:30 | You can summarize the part that due to saliva, starch became no longer starch. |
| 00:23:34 | Lastly, Benedict's solution. It's good. |
| 00:23:37 | Only in B, only in B, has Benedict's solution reacted. This means that in B the starch has disappeared and what was made instead? |
| 00:23:48 | Sugar. |
| 00:23:50 | It will be good if you can summarize that part. Okay? |
| 00:23:56 | All right, since it has taken a long time, I would like to listen to each group's result now. So, be ready to listen to everyone. |
| 00:24:07 | Now, everyone's- Ayamoto-san, okay? I will ask the results of each group. First, how the iodine reacted? For example, A was like this, B was like that. |
| 00:24:24 | Or A and C were the same... It will be good if you can present the results in that way. |
| 00:24:27 | Rock, paper, scissors... Rock, paper, scissors will do. |
| 00:24:34 | And number two. Benedict's solution. We added Benedict's solution to A and B and heated them. |
| 00:24:41 | Please describe what happened. Up to this point are the results. |
| 00:24:43 | The conclusion is next. First, I will ask you about the results. I think I first want to ask you about the results. |
| 00:24:50 | Where should I start? The results. |
| 00:25:01 | Shall we start here? There? There? Over there? |
| 00:25:06 | Group four, shall we? Okay. I see. Let's start with group four. It doesn't matter where we start. All right, please tell us your results. |
| 00:25:16 | Please listen. Hey, Ayamoto, this is the second time. |
| 00:25:22 | Please go ahead. |
| 00:25:23 | A, B... oops. A, C, and D were bluish purple the whole way through. //B became paler little by little. |
| 00:25:28 | //Yes. All the wa- |
| 00:25:31 | From which point did it start getting pale? |
| 00:25:32 | From about the third one, it started //getting paler. |
| 00:25:36 | //Yes. Yes. A, C and D are all bluish purple, but... Oh, please don't sit down yet. B started getting paler from about the third one. That was the report. |
| 00:25:50 | And how about the Benedict's solution? |
| 00:25:54 | The Benedict's solution in test tube A did not turn to reddish brown. |
| 00:26:00 | Yes. |
| 00:26:01 | B changed from blue to green, and when we kept heating it, it turned to reddish brown. |
| 00:26:07 | That was a wonderful way to say that. It turned from blue to green, and when it kept being heating, it turned to reddish brown. |
| 00:26:14 | So, in other words, B reacted. I see. |
| 00:26:17 | Well then, group five. Please report your results. |
| 00:26:28 | Go ahead. |
| 00:26:34 | You only have to say it. |
| 00:26:37 | A... The first one was bluish purple... and the second one did not change- |
| 00:26:52 | Did not change, does that mean that it was bluish purple? |
| 00:26:54 | Yes. |
| 00:26:55 | Then? |
| 00:26:57 | And the fifth one was (inaudible). |
| 00:27:00 | The fifth one? Did you just jump to the fifth? Huh? |
| 00:27:07 | It became weaker and weaker. |
| 00:27:09 | A got weaker and weaker? Huh? Is it reversed? |
| 00:27:17 | Wait a minute. In which ones did you put saliva and starch? |
| 00:27:22 | B and D. |
| 00:27:23 | B and D. You put saliva in B and D, but A's color changed from purple to a weak purple, is that right? I see. And then? |
| 00:27:31 | And B started losing its color after three minutes. |
| 00:27:37 | This one, too, started losing its color? |
| 00:27:41 | Yes. |
| 00:27:42 | I see. Then? |
| 00:27:46 | C... didn't change at all. |
| 00:27:53 | All bluish purple. And? |
| 00:27:56 | D... the color got weaker after 5 minutes. //The rest did not change. |
| 00:28:01 | //After 5 minutes- |
| 00:28:03 | The rest of the part were bluish purple. I see. Then what about the Benedict's solution? |
| 00:28:12 | A became dark green, //and B was reddish brown. |
| 00:28:14 | //Yes. |
| 00:28:18 | Ah, so only B reacted. I see. Group five has reported that A seemed to become pale, too. I see. Then, group six, please. |
| 00:28:31 | A and C were bluish purple all the way, B changed from dark bluish purple to pale bluish purple- |
| 00:28:43 | I see. Okay. |
| 00:28:45 | D was bluish purple for about three minutes, and after that it slowly turned pale. |
| 00:28:54 | I see. Then, what about the Benedict's solution? |
| 00:28:58 | A and B both became reddish brown. |
| 00:29:02 | I see, I see. Both of them became reddish brown. I see. Okay, group seven, please. |
| 00:29:12 | A and C and D were all bluish purple, and B started off bluish purple and became lighter. |
| 00:29:22 | From what point did it start getting lighter? |
| 00:29:23 | From the beginning. |
| 00:29:25 | Oh, I see, it got lighter from the beginning. I see. Then what about the Benedict's solution? |
| 00:29:31 | Test tube A was pale reddish brown. |
| 00:29:36 | Yes. Pale-// |
| 00:29:37 | //And B, dark reddish brown. |
| 00:29:40 | I see. Well... which one is the closest? This one I believe. Please take a look at this. |
| 00:30:00 | This one is the same test results of students like you- I wonder which class it was? Class four, class five, or class three? |
| 00:30:06 | The results of students like you in those classes. |
| 00:30:11 | Although we heard slightly different test results in this class, basically A and C are all bluish purple. The reason is that we put only starch in A and C, right? |
| 00:30:32 | So there is only starch and although the temperature is different, the starch remains starch from beginning to end. |
| 00:30:41 | So, many of you have reported that the bluish purple continued all the way, although some have reported that it got pale around here. |
| 00:30:51 | The question is B and D. The question is B and D. |
| 00:30:55 | There is saliva in the starch in B and D. We see a reaction in both B and D; that is, their color eventually gets lighter. |
| 00:31:07 | Does that mean there is starch or not? |
| 00:31:11 | It's disappearing. |
| 00:31:12 | It's disappearing, right? It doesn't, right? It is disappearing. The reason why is probably because we put saliva in them... that leads to our conclusion. |
| 00:31:22 | In addition to that, when we look at B and D more carefully, the rate that saliva disappears, no, sorry, the rate that starch disappears, when we compare B and D, which is faster? |
| 00:31:32 | B. |
| 00:31:33 | B is faster, right? B is faster. What was the conditional difference between B and D? |
| 00:31:39 | Temperature. |
| 00:31:40 | Temperature. B is... warm. As warm as body temperature. D is cold. |
| 00:31:47 | When we compare these, this one works the best, and I think that it will be good if you can include things like that in the conclusion. |
| 00:31:57 | And then there was such group... not this one, this one. |
| 00:32:07 | This one also has similar results, right? A and C have only starch, so they are bluish purple all the way through. |
| 00:32:15 | They put saliva in B and D, but in B, after about two minutes there was already no reaction for starch. |
| 00:32:24 | There was no starch at this point. |
| 00:32:26 | In D, the reaction to starch got weaker and weaker, and there was no starch at this point, then it revived. I don't get this. I wish this one weren't here. |
| 00:32:38 | But we see the color got weaker and weaker. |
| 00:32:43 | Then there is this one. This one is amazing. We discovered a new type of human. |
| 00:32:48 | [laughter] |
| 00:32:50 | Do you see? A and C are okay. In B, it suddenly disappeared here. More over in D, the starch suddenly disappeared here. |
| 00:33:03 | I won't say whose it was. It was Hiroshi Wakai's. |
| 00:33:06 | [laughter] |
| 00:33:08 | All right. Anyway, all you need to understand is in B and D, the starch has changed to something else. |
| 00:33:17 | In addition to that, we added Benedict's solution. We put Benedict's solution in A and B. |
| 00:33:23 | Look at this. I think it should react and become something like this. |
| 00:33:28 | A has only starch in it. |
| 00:33:32 | From this color, we cannot say it has reacted, when we put this against a florescent light and look at it through the light. |
| 00:33:40 | This one did. It got thicker and became reddish brown. It is the color of carrot juice. |
| 00:33:47 | When it reacts like this, we can judge that there is sugar in it. Actually, there seems to be sugar in B. |
| 00:33:56 | I wish to include this content in our conclusion. |
| 00:34:02 | First, the conclusions from the results of the iodine reaction. Second, the conclusions from the results of the Benedict's solution. These two. Can you present them? |
| 00:34:21 | We had eye contact. Group eight? Please. |
| 00:34:30 | The iodine reaction: When saliva is mixed with starch, it becomes no longer starch. |
| 00:34:36 | Yes. |
| 00:34:37 | And the rate in which starch disappears is faster when we heat it. |
| 00:34:40 | Mm, mm, mm. |
| 00:34:42 | Concerning the reaction to Benedict's solution, when starch is mixed with saliva, sugar is formed. |
| 00:34:48 | Mm. |
| 00:34:49 | That's it. |
| 00:34:50 | Mm, that's it? I see. That's good. That's good. That's good. |
| 00:34:58 | Next, group one. Can you do it? |
| 00:35:07 | Ryuutaro? or //Takashi? |
| 00:35:08 | //Is only the first point, okay? |
| 00:35:09 | Huh? |
| 00:35:10 | The first point. |
| 00:35:11 | Only the first point. That's fine. Since the conclusion is difficult. Okay, go ahead. |
| 00:35:14 | When we compare test tubes A and B, A does not change, but the starch in B, in which saliva is added- |
| 00:35:29 | The starch in B was dissolved by the saliva little by little. Yes. Yes. That's fine. When we compare A and B, we can see that in B, in which saliva was added, the starch has dissolved little by little. Okay. That's fine. |
| 00:35:41 | Okay, group two. |
| 00:35:44 | Uh- |
| 00:35:47 | What do you mean by, "uh"? |
| 00:35:49 | Human's saliva has a function of dissolving starch. And the closer its temperature is to body temperature, the faster the rate. |
| 00:36:02 | B- oops- the second point is that the human saliva has the function of changing starch into sugar. |
| 00:36:14 | Haa. I am amazed. Wonderful. |
| 00:36:18 | Actually, I am the one who summarized it. |
| 00:36:19 | [laughter] |
| 00:36:23 | I see. That was a nice presentation. It was very logical, good conclusion. Then, how about the group three? |
| 00:36:30 | Yes. |
| 00:36:31 | Yes. |
| 00:36:33 | In terms of the reaction with iodine, the one with saliva became less and less starchy. |
| 00:36:40 | Yes. |
| 00:36:41 | Then, in terms of the reaction with Benedict's solution, by adding saliva, starch became sugar. |
| 00:36:52 | Yes. I think it's very good. This was also a nice presentation, don't you think? I think it's good. |
| 00:36:57 | Well then, I will summarize each group's presentation into sentences, so please write them down in your notebook. I think we can summarize like this. |
| 00:39:18 | Oh, maybe it is hard to see. Should I lower this? |
| 00:39:26 | Teacher, I think the OHP is not very useful. |
| 00:39:28 | What are you talking about? I pointed to them like this. |
| 00:39:31 | Isn't it faster to use that one? Rather than using the heavy OHP? |
| 00:39:32 | No, you don't understand it. Because of this everyone understood well. Well, don't say that. |
| 00:39:45 | Ok, did everyone finish writing? |
| 00:39:48 | Um, from this experiment, we can see these two things, as you all noticed. |
| 00:39:55 | The first one is that saliva seems to have the function of changing starch into something else. |
| 00:40:03 | Saliva may have a function which changes starch into something else. |
| 00:40:09 | Moreover, from the iodine reaction and Benedict's solution's reaction, starch into something else- so, what is it? Sugar. We wonder if there is a function of changing starch into sugar. |
| 00:40:23 | As I said in the beginning of the class, starch is a long chain. A long molecule. At a glance, it is a huge molecule. |
| 00:40:32 | But sugar is a small molecule. A short chain. From this, we understand that saliva has the function of breaking a big chain of starch into a small chain of sugar. |
| 00:40:50 | Next, the second point. Um, from the conditional differences between B and D, the difference in the temperature, |
| 00:40:59 | I think we understand that saliva works best when the temperature is close to body temperature. |
| 00:41:10 | All right, please open your textbooks to page 94. There will be a part you should underline. So be prepared and listen. |
| 00:41:22 | All right, we will start. Page 94. |
| 00:41:29 | After "from experiment two," please underline. |
| 00:41:33 | "Starch is dissolved by saliva and changes into sugar." Please underline up to this point. "Starch is dissolved by saliva and changes into sugar." |
| 00:41:48 | Next you don't have to underline. "Also, because this sugar's molecule is smaller than starch, it can go through cellophane membrane." Okay, underline after this. |
| 00:41:58 | "Other than saliva, such fluids as gastric juice and pancreatic juice, which have the function of digesting food, are called digestive fluid." Underline up to here. |
| 00:42:09 | Next. This will be a long one too. |
| 00:42:12 | "In digestive fluid..." Underline here, "In digestive fluid, there are different kinds of digestive enzymes. |
| 00:42:18 | "Under appropriate temperature it dissolves components in food and changes them into nourishment which is easily absorbed." |
| 00:42:28 | Mm. Our textbooks are all marked with red now. |
| 00:42:32 | The next (section) too. This is all important. This page will be all marked with red. Sorry. Underline the next (section). |
| 00:42:36 | "Each digestive enzyme dissolves particular food components such as: digestive enzymes in saliva (amylase) work on starch, |
| 00:42:41 | "digestive enzymes in gastric juice work on protein, and so on." Underline up to here. |
| 00:42:53 | It was a long explanation, but I will summarize for you to write in your notebooks. Since it is hard to understand otherwise. |
| 00:46:18 | //Can you see it? |
| 00:46:57 | I wonder whether people can see at the bottom. Chiho, can you see this? |
| 00:47:01 | Can you see this? |
| 00:47:02 | (inaudible) |
| 00:47:03 | Can you see? Sorry. |
| 00:47:07 | Can you see this part, gastric juice? |
| 00:47:08 | Yes. |
| 00:47:09 | You can. Sorry. This is very low. |
| 00:47:28 | Are you all right? Oh, I should underline here. |
| 00:47:47 | Today's topic, saliva. Which has the function of dissolving starch into sugar. Saliva. |
| 00:47:54 | Saliva is called digestive fluid. Digestive fluid. Fluid to dissolve starch into sugar. Saliva is digestive fluid. |
| 00:48:03 | Fluid which digests food is called digestive fluid. Digestive fluid is not only saliva. There is gastric juice which is in the stomach. |
| 00:48:13 | When you throw up, you have a sour taste in your mouth. That's gastric juice. Go deeper down and we have pancreatic juice in the pancreas, or bile in the gallbladder, and so on. |
| 00:48:26 | We call these fluids, which digest food, "digestive fluids." In addition, in the digestive fluids, there are digestive enzymes. |
| 00:48:37 | We read this as "enzymes." You didn't write "oxygen" in your notebook, did you? |
| 00:48:44 | Are you okay? It's not oxygen. It's enzymes. Okay? Chinese characters? |
| 00:48:51 | In digestive fluid, there are digestive enzymes. These digestive enzymes are determined by the food components they dissolve. |
| 00:49:02 | For example, saliva works only on starch, which we experimented with this time. You must have learned in home science. |
| 00:49:07 | Five major nutrient categories. Protein, fat. There are many nutrient categories, but saliva only works on starch. |
| 00:49:18 | And gastric juice in the stomach, which I mentioned before, works only on protein. |
| 00:49:25 | Such digestive enzymes which have specific functions are included in digestive fluids. |
| 00:49:33 | This is a little bit difficult, so we will look at this in detail in the next lesson. |
| 00:49:41 | All right, we will finish today's lesson, but please turn in your report. All right, that's it. |
| 00:49:49 | Stand up. |
| 00:50:06 | Bow. |
| 00:50:07 | Yes. |
| 00:50:11 | Please turn in your reports. |